With security being an increasing concern, many methods have been utilized to reduce the potential occurrence of injury and damage due to the force of explosions. In particular, protection is desired against inward (i.e., away from the direction of the explosion) displacement of the frame of a window or door due to the blast. Typically, protection from explosions has been provided by the use of passive barriers, such as steel reinforced doors and laminated windows. In order to maintain an adequate level of protection, as the risk has historically increased, new barrier systems have increased in weight, thickness and structural and material complexity. While this may be acceptable in certain situation where ascetics are not a concern, such a bank vault or the like, in uses such as residential homes or office buildings requiring such protection, such solutions are inadequate. In addition, they may draw attention to the high security of the building, rendering it a target for an attack.
U.S. Pat. No. 6,922,957 discloses an opening in a building wall closed by a building closure such as a window or door. A mounting part of the closure arrangement is received in a space between two countersupport surfaces formed by a U-channel or opposite L-members that protrude perpendicularly from the sill or jamb surface of the wall bounding the opening. Mounting brackets secure the U-channel or L-members to the wall. On one or both sides, a respective damping element is interposed between the mounting part and the respective adjacent countersupport surface. The damping element may be a plastically deformable metal strip. When an explosion force acts on the closure arrangement, the damping element is first plastically deformed to absorb energy, before the remaining force is transmitted into the building wall. The two damping elements on opposite sides damp forces from the positive and negative pressure waves of to the explosion.
U.S. Pat. No. 6,216,401 discloses a blast resistant window framework and elements thereof. It describes the construction of the sash section for holding a window pane, being capable of effectively withstanding blast pressure if applied to it. This being achieved by the sash section comprising a main member enabling inter-engagement between the profiled sash member and the outer frame; a window pane holding member for accommodating and securing an end section of window pane in said sash profiled member; a reinforced member designed to support the end portion of the window pane and transmit blast pressure, if incidentally applied to the window pane, to the main member. The structured being resilient to blast pressure due to the applied blast pressure being transmitted to the main member, which deforms to utilize the energy. The sash section may be a profiled body or be composed of multiple inter-engaged segments.